This is a 95 129 chassis car and as such has pyrotechnic tensioners so disassembly of the retractor should be at the very least done with same caution one would employ screwing with an airbag installation!

You will likely need to find some information specific to the system in that more modern car, there may be a sensor that detects the seat belt interlocking that causes a reaction in the SRS system. Might have something to do with seat positioning etcetera, someone who owns or specifically works on the 129 chassis would know more about that. You can always buy a DVD manual from MBUSA that would explain how that system works.